Topsoil Calculator
Estimates use screened topsoil at 1.35 tons per cubic yard. Actual weight varies with moisture, so order about 10 percent extra for grading and settling.
How Much Topsoil Do You Need?
A topsoil calculator works out how much soil your project needs. Enter the length and width in feet, the depth in inches, and your bag size, and it returns cubic feet, cubic yards, weight in tons, and the number of bags to buy. Use it before ordering to avoid a second delivery.
Topsoil is sold by volume, not weight, so results focus on cubic feet and cubic yards first. Bulk suppliers quote by the cubic yard, while bagged soil is labeled in cubic feet. Knowing both lets you compare bulk and bagged prices fairly.
How to Use the Topsoil Calculator
Follow these steps to get an accurate estimate for any rectangular area.
- Measure the area. Measure the length and width in feet. For an irregular shape, split it into rectangles, calculate each one, and add the results.
- Choose your depth. Enter depth in inches: 1 to 2 inches for topdressing, 4 to 6 inches for a new bed, and 8 to 12 inches for a raised bed or leveling.
- Enter your bag size. If you plan to buy bagged soil, enter the bag volume in cubic feet. The default is 2 cubic feet, a very common bag size. Leave this step out if you are ordering in bulk.
- Read your results. The calculator shows cubic feet, cubic yards, tons, and bags rounded up. Always round up, since a partial bag still has to be bought.
- Add a buffer. Order about 10 percent extra. Soil settles after watering, and uneven ground takes more fill than a flat rectangle on paper.
Topsoil Calculator Formula
The math behind the calculator is simple, and you can check it by hand for any project:
- Cubic feet = length (ft) x width (ft) x (depth in inches / 12)
- Cubic yards = cubic feet / 27
- Tons = cubic yards x 1.35 (the density of screened topsoil)
- Bags = cubic feet / bag size, rounded up to the next whole bag
Dividing depth by 12 converts inches to feet so all dimensions share a unit. There are 27 cubic feet in one cubic yard, which is why bulk orders are quoted in yards. The 1.35 tons per cubic yard figure applies to screened, loose topsoil; wet soil can weigh more, so treat tonnage as an estimate.
Topsoil Calculator Examples
These verified examples show how the formula works for two common projects:
| Project | Size | Depth | Cubic feet | Cubic yards | Tons | Bags (2 cu ft) |
|---|---|---|---|---|---|---|
| Lawn topdressing | 30 x 20 ft | 4 in | 200 | 7.41 | 10.00 | 100 |
| Raised garden bed | 4 x 8 ft | 12 in | 32 | 1.19 | 1.60 | 16 |
For the lawn, 30 x 20 x (4/12) = 200 cubic feet, or 7.41 cubic yards, 10.00 tons, and exactly 100 bags at 2 cubic feet each. The raised bed works the same way: 4 x 8 x (12/12) = 32 cubic feet, or 1.19 cubic yards, 1.60 tons, and 16 bags.
Choosing the Right Depth
Depth matters more than most people expect, because doubling the depth doubles the soil needed. A 1-inch topdressing refreshes a lawn without smothering grass, while a new lawn from seed or sod needs 4 to 6 inches for roots to establish. Vegetable beds do best at 8 to 12 inches, since most crops root deeply.
For a low spot, measure depth at several points and use the average. A dip 6 inches deep in the middle but 2 inches at the edges needs less soil than a flat 6-inch layer.
Bagged vs Bulk Topsoil
Small projects usually favor bags: a raised bed needing 32 cubic feet takes just 16 bags, and you can carry them exactly where they are needed. Large projects favor bulk delivery, since a 7.41 cubic yard lawn job would need 100 bags, which costs far more per yard than a truckload and creates a lot of plastic waste.
When comparing prices, convert everything to cost per cubic yard. A bagged price looks small until you multiply it out, and a bulk price looks large until you divide it by the yards delivered. Also check delivery fees, since bulk delivery may be included while bags may need a separate trip.
Topsoil is not the only material a yard project may need. If you are building a patio or a path alongside your new bed, a concrete volume estimator will work out the mix for the slab. For planting beds that also need a mulch layer on top, the mulch coverage tool converts the same area measurements into cubic yards of mulch. A driveway or drainage trench calls for a different material entirely, so check the gravel quantity calculator before ordering stone. And if your project includes painting a fence, shed, or raised bed frame, the paint amount estimator tells you how many gallons that job will take.
Frequently Asked Questions About Topsoil
How many cubic yards of topsoil do I need?
Multiply length by width by depth in feet, then divide by 27. A 30 x 20 foot lawn at 4 inches deep needs 200 cubic feet, or 7.41 cubic yards. The calculator above also gives bags and tonnage.
How many bags of topsoil make a cubic yard?
One cubic yard equals 27 cubic feet. With 2 cubic foot bags, you need 14 bags per yard (27 divided by 2 is 13.5, rounded up). With 1 cubic foot bags, you need 27.
How much does a cubic yard of topsoil weigh?
A cubic yard of screened topsoil weighs about 1.35 tons, or roughly 2,700 pounds. Wet topsoil weighs more, sometimes up to 1.6 tons per yard, so allow extra if you are hauling it yourself.
How deep should topsoil be for grass?
New grass needs 4 to 6 inches of topsoil for healthy roots. For topdressing an existing lawn, spread only 1 to 2 inches at a time so grass blades are not buried.
How much topsoil do I need for a raised bed?
Multiply bed length by width by depth in feet. A 4 x 8 foot bed filled 12 inches deep needs 32 cubic feet, or 16 bags of 2 cubic foot soil. Measure the true inside height of your bed frame.
Should I order extra topsoil?
Yes, order about 10 percent extra. Soil settles after rain and watering, and uneven ground takes slightly more fill than the flat math suggests. A small surplus beats a second delivery fee.
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